1. Field of the Invention
The invention is bisphosphonic acids, their esters and pharmaceutically acceptable salts which are useful as anti-arthritic agents.
2. Description of the Related Art
U.S. Pat. No. 4,746,654 discloses bisphosphonates useful as anti-inflammatory agents.
Australian Patent A-5 1534/85 discloses bisphosphonates useful in treating abnormal calcium and phosphorous metabolism and useful in treating arthritis.
U.S. Pat. No. 3,683,080 discloses polyphosphonates, in particular diphosphonates useful in inhibiting anomalous deposition and mobilization of calcium phosphate in animal tissue.
DE 3,719,513-A (Derwent 89-000580/01) discloses diphosphonic acid derivatives useful in treatment of disorders of calcium metabolism.
WO88/06158 discloses the reaction of activated methylenes with vinylidene diphosphonates.
International Publication Number WO90/12017 for International Application Number PCT/US90/01106 discloses geminal bisphosphonic acids and derivatives thereof as anti-arthritic agents.
J6 3185-993-A discloses ethanones and J6 3295-595-A discloses propanones similar to the 4,4-diphosphonic acid (ester)-1-butanones of the present invention.
Synthesis, 661 (August 1991) discloses the compound of Example 47 of the present invention in its compound 3e.
The present invention is to compounds which while anti-arthritic are not prostaglandin synthetase inhibitors which is an advantage in that the side effects of the prostaglandin synthetase inhibitor anti-arthritic compounds are eliminated.